1. Field of the Invention
The present invention relates to wireless communications systems and in particular, a system which tracks the current and historical locations of a locator device worn or carried in some manner by a person.
2. Background Art
There has been a long felt need for the ability to locate "lost" people with respect to a geographical reference. Perhaps the most significant need is that for locating children who are lost or have been abducted. There are a variety of systems which exist that utilize a Global Positioning System (GPS) for determining a person's position relative to geographical coordinates. In accordance with such systems, a person wears a small device which receives and triangulates signals from each of three geostationary satellites, and determines the geographical coordinates of the device's current location.
Many of the prior art systems which use a GPS device and system, notify the specific person wearing the device of their present location. Some systems further couple the GPS receiving device to a transmitter, allowing the transmission of a person's current positional coordinates to a centralized receiver for the purpose of establishing that person's location in the event of an emergency.
These prior art systems are designed to perform specific functions in response to either the general transmission of the device's current geographical coordinates, or the activation of an emergency distress signal on the device. These specific functions are generally limited to emergency procedures carried out by government agencies. Moreover, these prior art systems are only capable of providing a person's current location to users who have direct access to the receiving system. This is typically a governmental agency, such as a 911 call center or police agency, who can only afford to monitor persons of immediate concern, i.e. those who are in immediate threat of severe bodily injury.
These prior art systems require either the person wearing the receiving/transmitting device, an internal mechanism in the device itself, or a network component that can physically monitor the device on a continuous basis, to trigger a transmission of current coordinates. It would be useful to enable a person, other than the individual wearing or carrying the device, to trigger an automatic location transmission on their demand.
U.S. Pat. No. 5,485,163 to Singer et al. (hereafter "Singer"), describes a system for locating a portable locator device in a communications network using cellular network technology. A button on the Singer device is used to trigger a transmission of current location coordinates, such as may be needed in the case of a kidnapping. But it does not describe the use of a GPS for determining a precise geographical location.
U.S. Pat. No. 5,583,914 to Chang et al., discloses an intelligent wireless signaling overlay for a telecommunication network. It utilizes a GPS locating device for determining the location of a signal termination for assistance in optimizing a transmission path.
U.S. Pat. No. 5,572,204 to Timm et al., discloses a system for requesting emergency or roadside assistance for a vehicle, utilizing a GPS to determine the vehicle's location.
Copending U.S. patent application, Ser. No. 08/575,196 filed on Dec. 20, 1995 (assigned to the assignee of the present invention), relates to a wireless communication device using GPS technology to determine a subscriber's location. This device automatically communicates the location of a subscriber to emergency services if an emergency button has been activated on the device. The art described in the aforesaid patent application only specifies auto-notification based on the activation of an emergency distress signal. It does not describe auto-notification based on movement thresholds or the remote triggering of the automatic transmission.
The prior art systems provide neither a translation to more commonly recognized geographical location references, such as addresses, graphical maps and zip codes, nor a general user interface which a first party, i.e. someone other than the device carrier (for example, a parent), may easily use to identify current and past locations of a second party, i.e. the device carrier (for example, a child). Furthermore, the prior art systems do not provide methods for accessing current and historical location data via the World Wide Web (Web) or a Voice Response Unit (VRU). Moreover, they do not enable a call center operator to assist the first party in determining the current location of the second party. These limitations are overcome, and other features are provided, by the present invention.